This invention relates to a pressure control device suitable for hydraulic brake control of a motor vehicle in systems such as, anti-lock brake systems and traction control systems for example.
Certain types of pressure control devices, such as some that are used in the automobile industry for antilock braking systems, include a plurality of solenoid valves. Each of these solenoid valves is equipped with a dome type valve body and a doughnut type coil. Each valve body is installed in a valve block which has brake fluid channels running therethrough. A cover, which protects an underlying control circuit board, is installed over the valve bodies and positioned adjacent the coils relative to the valve body. The cover is installed on the valve block, in a position such each valve body is surrounded by a corresponding coil.
With regard to the subassembly of the coil and valve body, a lead wire terminal extends directly above the coil and is electrically connected with the circuit board by soldering. Because the coil moves during operation, it is critical to interconnect the coil and the circuit board in a manner which will not disturb or stress the soldered electrical interconnect. To address this critical feature, it is known to provide an interrupting conductor which has some degree of flexibility so as to help present stressing of the electrical interconnect. Among the flexible components that may be included in such interrupting conductors are, e.g., bus bars, lead wires, or accordion bars, which are positioned between the coil and the control circuit board. The flexibility of the interrupting conductor helps to reduce the transmission movements of the coil to the circuit board and soldered electrical interconnect. This technology is disclosed in the Japanese Patent Application Publication Nos. 9-26773b, 9-263223, and 9-511964.
The conventional constructions as described above have the disadvantage that, in order to provide the desired flexibility, an additional part, such as an interrupting conductor is required, which leads to higher manufacturing and assembly costs, thereby making the component more expensive to the end user. The conventional arrangements are produced with the interrupting conductor embedded in a cover, which requires an installment tool to hold the parts during assembly. This also increases the cost of manufacturing and assembly, due to the additional tool required and the increased complexity of the assembly process. The interrupting conductor must be designed not to interfere with other components as well as be designed to be of a minimum length. One end of the interrupting conductor must be electrically connected to the lead wire terminal of the coil and the other end to the control circuit board. This, compared to a construction which directly connects the lead wire terminal of the coil to the control circuit board, this construction is considerably more complex and costly to manufacture.